1.6 The Phosphorus Cycle

00:07:41
https://www.youtube.com/watch?v=bt-_wvJ-tFI

Sintesi

TLDRThe phosphorus cycle is essential for life, particularly in forming nucleic acids and ATP. It involves a slow process primarily sourced from rocks that contain phosphorus minerals, with reservoirs in the lithosphere and biosphere. Plants absorb phosphates from soil or water, which can then pass through food webs in ecosystems. Lacking an atmospheric component, the cycle does not allow for rapid returns of phosphorus, making it a limiting nutrient in many environments. Human activities significantly affect the cycle, contributing to problems such as eutrophication through runoff from fertilizers and waste.

Punti di forza

  • 🌱 Phosphorus is crucial for DNA and RNA synthesis.
  • ⚒️ The main source of phosphorus is from rock erosion.
  • 🌊 Phosphates enter the biosphere through water and soil.
  • 🔄 The cycle lacks an atmospheric component.
  • 🐾 Phosphorus is often the limiting nutrient in ecosystems.
  • 💧 Human activities lead to phosphorus runoff into water bodies.
  • 🧪 Excess phosphorus can cause harmful algal blooms.
  • 🌍 Phosphorus is slow to cycle compared to carbon and nitrogen.
  • ⚠️ Mining and fertilizers impact the phosphorus cycle significantly.
  • 🌾 Decomposers recycle phosphorus back into the soil.

Linea temporale

  • 00:00:00 - 00:07:41

    The phosphorus cycle is an essential ecological process, comparable to the nitrogen and carbon cycles, but less frequently discussed. Phosphorus is primarily found in biological molecules such as nucleic acids, where it exists as phosphate groups. The cycle involves reservoirs like the lithosphere (rocks and sediments rich in phosphorus minerals) and the biosphere, with erosion being the key process that redistributes phosphorus. Plants absorb phosphates from the soil or water, which can be returned to these reservoirs through decomposition. Unlike the carbon and nitrogen cycles, the phosphorus cycle lacks an atmospheric component, leading to a slower cycle overall and limiting the availability of phosphorus in ecosystems. Consequently, phosphorus can be a major limiting factor for growth, as it is vital for DNA, RNA, and ATP production. Human activities impact the cycle significantly through mining, the use of fertilizers, and agricultural runoff, leading to issues like eutrophication in aquatic systems.

Mappa mentale

Video Domande e Risposte

  • Why is phosphorus important for living organisms?

    Phosphorus is essential for the formation of nucleic acids and ATP, crucial for energy storage and transfer in cells.

  • What are the main reservoirs of phosphorus?

    The main reservoirs of phosphorus include the lithosphere (rocks and sediments) and the biosphere (nucleic acids).

  • How does the phosphorus cycle differ from other biogeochemical cycles?

    Unlike the carbon and nitrogen cycles, the phosphorus cycle does not have an atmospheric component and is dependent on the rock cycle.

  • What human activities impact the phosphorus cycle?

    Human activities such as mining phosphorus, using phosphorus-rich fertilizers, and discharging sewage add excess phosphorus to ecosystems.

  • What can happen due to excess phosphorus in water bodies?

    Excess phosphorus can cause eutrophication, leading to algal blooms and reduced oxygen levels in water.

  • How do plants obtain phosphorus?

    Plants absorb phosphates from the soil or water, which are released through erosion and decomposition.

  • What role do decomposers play in the phosphorus cycle?

    Decomposers break down organisms, returning phosphates to the soil or water.

  • What is the significance of the rock cycle in the phosphorus cycle?

    The rock cycle is crucial as it is the source for phosphorus through sedimentation and erosion.

  • What is eutrophication?

    Eutrophication is the over-enrichment of water bodies with nutrients, leading to algal blooms and oxygen depletion.

  • Why is phosphorus considered a limiting factor in ecosystems?

    Phosphorus is often the least abundant nutrient in ecosystems, limiting the growth of organisms.

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Scorrimento automatico:
  • 00:00:00
    all right get ready for the shortest
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    next set of lecture notes I think I will
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    ever have made on a completely new thing
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    to most of y'all which is the phosphorus
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    cycle so you talked about the nitrogen
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    cycle carbon cycle when you were a
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    freshman when you were doing ecology but
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    you probably haven't talked about the
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    phosphorus cycle yet phosphorus is also
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    going to be an important atom for living
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    things so if you
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    um bear with me let's get go ahead and
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    start talking about what atoms and
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    molecules contain phosphorus so in as
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    far as biological molecules go organic
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    molecules it's just nucleic acids you
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    may have talked about your freshman year
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    the different elements that you'll find
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    in uh different biomolecules and you may
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    remember that they may have talked about
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    Chomp which is carbon hydrogen oxygen
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    nitrogen and phosphorus being present in
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    nucleic acids because they have have
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    phosphate groups so any sort of compound
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    that's got a phosphate ion which is a
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    po4 and it is a negatively charged ion
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    is going to be a
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    was going to be a phosphate group
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    okay so now let's talk about the
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    reservoirs in the phosphorus cycle it is
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    mostly going to involve the rock cycle
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    um and so a major reservoir for
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    phosphorus is going to be the
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    lithosphere by which I mean rocks and
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    sediments that are going to have
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    phosphorus containing minerals so the
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    source of these uh phosphorus containing
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    molecules is going to be sedimentation
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    so you have something that is heavy with
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    in phosphorus falls to the ground falls
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    to the bottom of a body of water and
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    that forms sedimentary rock and then
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    that goes into the rock cycle and
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    usually the source of
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    um
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    phosphorus for other parts of the
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    phosphorus cycle is going to be erosion
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    of these rocks so it's a very slow cycle
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    very slow process so then you have the
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    biosphere which is going to contain uh
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    consist mostly of nucleic acids and the
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    source is that producers are generally
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    going to absorb phosphates from either
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    the soil or the water that got deposited
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    there from erosion or runoff and then
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    decomposition is going to take of those
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    phosphorus containing molecules and
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    probably produce phosphates that are
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    going to go back into the soil or the
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    water and phosphates can dissolve in
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    water so there is a water reservoir as
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    well
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    so here we see in general the phosphorus
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    cycle notice there's nothing in the
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    atmosphere the only reason why we have
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    something up there is precipitation
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    because it's going to cause weathering
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    and erosion that is going to release
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    phosphates which will be in runoff that
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    can then enter water or they can end up
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    forming part of soil plants are going to
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    take in phosphates and then those can be
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    eaten by other organisms or when
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    organisms plants Etc die then that can
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    be broken down by decomposers which can
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    put phosphates either into the soil or
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    phosphates can enter the water so then
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    you have dissolved phosphates can be
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    taken up by Plankton and other producers
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    in aquatic biomes
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    and it can then join the food web in
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    Marine or aquatic ecosystems and then
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    decomposition will then add more
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    phosphates back into the water however
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    sometimes things are going to go into
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    sedimentation where you'll have some
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    phosphorus Rich sediment that ends up
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    getting compacted and then turned into
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    rock and so then you have
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    entering the major reservoir of the
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    phosphor cycle Rock itself
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    so there is no atmospheric component in
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    the phosphorus cycle you do not have a
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    gaseous form of phosphorus it's kind of
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    too heavy for that so even if you had
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    something in the atmosphere it'd usually
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    be dust which would then come out next
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    time it rained so because of this
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    um it's really going to limit how
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    phosphorus containing compounds can
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    return from Ocean back to land because
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    if you look at the carbon cycle you know
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    carbon dioxide can go from the ocean to
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    the the air and then that can be taken
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    up by plants so that it can go into
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    terrestrial ecosystems nitrogen you can
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    have nitrogen in the water but then you
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    can also have denitrifying bacteria
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    return that to the air in phosphorus you
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    don't have an atmospheric component and
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    so that can end up limiting the amount
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    of phosphorus that you have available in
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    Aquatic and terrestrial ecosystems
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    and since it's so dependent on the rock
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    cycle phosphorus is a much slower cycle
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    than the other elements so it's going to
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    take a lot longer to to remove
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    phosphorus from the environment and also
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    put it back into the environment from
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    Rock
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    so this leads to the fact that
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    in an ecosystem phosphorus can be a
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    major limiting factor and this is
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    without human activity affecting the
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    phosphorus cycle so let's say the square
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    here this rectangle represents an
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    ecosystem
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    you'll have a lot of water in that
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    ecosystem so unless you're in like a
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    desert environment water doesn't really
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    limit the life that can grow there
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    you'll have plenty of carbon there as
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    well so carbon's not really going to
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    limit what can grow there you've also
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    usually got a bunch of nitrogen as well
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    but notice phosphorus is going to be
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    lowest in abundance there's going to be
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    less of it and so since there's less of
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    it
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    um you know without phosphorus you can't
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    make DNA you can't make RNA and you also
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    can't make ATP and if you remember ATP
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    is what for a cell it is energy
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    so when you don't have enough phosphorus
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    you can't make new cells and you may not
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    be able to power the cells that you have
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    so the amount of phosphorus in an
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    ecosystem can limit how many organisms
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    can be supplied there
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    and that kind of leads to how humans
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    impact the phosphorus cycle we mine
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    phosphorus we'll dig up Rock That's
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    Heavy in phosphorus or we'll find other
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    sources of phosphorus for example guano
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    which is mostly bat poop
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    and is heavy in phosphorus and is often
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    used as a fertilizer and we'll use these
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    things as fertilizers for growing crops
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    or in our yards
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    then also we have those large
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    um
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    they're called cafos animal feedlots
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    where you have a lot of poop or
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    excretion being released which is going
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    to build up phosphorus in the soil
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    humans also poop and that goes into
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    sewage and that can be a source of
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    phosphorus detergents actually contain a
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    lot of phosphates and we'll talk more
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    about that in the future when we talk
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    about some pollutants you can also have
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    some industry producing phosphorus as
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    well a lot of this stuff ends up in the
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    soil which can then end up draining into
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    the water and that can cause something
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    called eutrophication which we talked
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    about briefly in the nitrogen cycle and
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    which we're going to talk about quite a
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    bit in the future
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    so that was the phosphorus cycle like I
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    said very quick very short and now we're
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    going to move on to energy which means
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    food webs and food chains so don't panic
Tag
  • phosphorus cycle
  • ecosystems
  • nucleic acids
  • biogeochemical cycles
  • human impact
  • eutrophication
  • fertilizers
  • decomposition
  • sedimentation
  • rock cycle